The subject matter disclosed herein relates to subterranean formation evaluation, and more specifically to evaluating geological formations disposed about a hydrocarbon extraction borehole.
Subterranean hydrocarbon deposits may be accessed by drilling a bore that extends from the surface of the earth to the hydrocarbon deposit, and then pumping hydrocarbons up to the surface through the bore. In some applications, a measurement tool may be run through the bore after the bore has been drilled to take measurements of the bore or the earth disposed immediately around the bore. However, because such systems are designed to measure formation properties along the axis of borehole they are inadequate for evaluating the formation far away from the borehole. Formation evaluation methods that depend on elastic wave propagation normally focuses on the refracted wave propagating along the walls of the borehole and other wavemodes that propagate within the bore along its axis. Microfractures and major fracture planes that extend tens of meters away from the borehole cannot be investigated with such conventional tools and methods. It would be beneficial to design a measurement tool capable of detecting small and large fractures that extend tens of meters away from the borehole that may act as storage or pathways for hydrocarbons.